One of the most common concerns for pool owners is the amount of diatomaceous earth (DE) to add to the filter. This is important for you to know because if the DE amount is too small, debris, oils, and dirt will become embedded into the grids, which will eventually ruin them.
Too much DE causes a condition called “bridging” when the powder builds up to the point where it reduces filter capacity and flows. While these problems occur when the DE amount is a great deal under or over what it should be, you should still be aware of how much DE to add to a sand filter.
Cleaning and New Filters
Whether you have a new filter installed or you are performing a cleaning, you will need one pound of DE for every 10 square feet of the filter. Cleanings should be done once or twice each year. The following guide will help you to determine the correct amount of DE for your pool’s filter size:
- A 24 square-foot filter requires 2.4 pounds of DE
- A 36 square-foot filter requires 3.6 pounds of DE
- A 48 square-foot filter requires 4.8 pounds of DE
- A 60 square-foot filter requires 6 pounds of DE
- A 72 square-foot filter requires 7.2 pounds of DE
After Backwashing
When you clean the pool filter, you will use a process called “backwashing.” This is done by utilizing the backwash valve on your filter to remove the dirty DE from the grids. Since this process does not extract all of the DE, you will add only 80 percent back after the cleaning is completed:
- A 24 square-foot filter will need 1.9 pounds of DE
- A 36 square-foot filter will need 2.8 pounds of DE
- A 48 square-foot filter will need 3.8 pounds of DE
- A 60 square-foot filter will need 4.8 pounds of DE
- A 72 square-foot filter will need 5.7 pounds of DE
Measuring DE Powder
You probably do not have a handy scale in your pool area and are wondering how to measure the DE. A common method is using a one-pound coffee can because it holds a half pound of DE. The problem with this approach is most one-pound coffee cans are now actually 13 ounces, which throws off the measurement. You can avoid this problem by purchasing a dedicated DE scoop, which is designed to measure exactly one-half pound of DE powder. After a full filter cleaning, divide the square footage by five to determine the number of scoops that you need. If you have done a backwashing process, divide the square footage by six.
Full cleanings and new filters:
- 24 square feet equals 5 scoops
- 36 square feet equals 7 scoops
- 48 square feet equals 10 scoops
- 60 square feet equals 12 scoops
- 72 square feet equals 14 scoops
After backwashing:
- 24 square feet equals 3 scoops
- 36 square feet equals 5 scoops
- 48 square feet equals 7 scoops
- 60 square feet equals 9 scoops
- 72 square feet equals 11 scoops
After you install a new filter or do a cleaning procedure, it is crucial for you to watch the pressure on the filter for 24 hours after adding the DE. This number can go up very quickly because the filter is catching extremely fine particles. If you are not sure how much DE to add to the sand filter, consult with a pool expert, or have the filter serviced regularly by a professional company.
Handling of DE
When handling DE, it is important to remember that it can be easily inhaled, causing lung irritation. Always wear a mask when scooping DE. In addition, DE is categorized as carcinogenic, and it may also cause skin reactions through direct contact. Check your local laws to ensure that DE is not prohibited from release into sewer systems or into the general environment. It should be noted that DE designated for gardening is not suitable for use in pool filters because it has not been heat-treated.
A backyard pool is not only a way to stay cool in the summer, but it also offers an opportunity for regular exercise and family bonding. Knowing exactly how much DE to add to the sand filter is an important maintenance step that will keep your pool healthy and sparkling for years to come.
